package juc;

import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;

public class TestProductorAndConsumerByLock {
    public static void main(String[] args) {

        Clerk clerk = new Clerk();
        Productor productor = new Productor(clerk);
        Consumer consumer = new Consumer(clerk);

        new Thread(productor, "生产者A").start();
        new Thread(consumer,"消费者B").start();
        new Thread(productor, "生产者C").start();
        new Thread(consumer,"消费者D").start();
    }

}

class Clerk {

    private int product = 0;

    private Lock lock = new ReentrantLock();

    private Condition condition = lock.newCondition();
    //进货
    public  void get() {
        lock.lock();
        try {
            while (product >= 1) { //为了解决虚假唤醒问题，应该总是使用在循环中
                System.out.println("货物已满");
                try {
                   condition.await();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
            ++product;
            System.out.println(Thread.currentThread().getName() + ": " + product);
            condition.signalAll();
        } finally {
            lock.unlock();
        }



    }

    //售货
    public void sell() {
        lock.lock();
        try {
            while (product <= 0) {
                System.out.println("货物已空");
                try {
                    condition.await();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
            --product;
            System.out.println(Thread.currentThread().getName() + ": " + product);
           condition.signalAll();

        } finally {
            lock.unlock();
        }
    }
}

class Productor implements Runnable {

    private Clerk clerk;

    public Productor(Clerk clerk) {
        this.clerk = clerk;
    }

    @Override
    public void run() {
        for (int i = 0; i < 20 ; i++) {
            clerk.get();
        }

    }
}

class Consumer implements Runnable {

    private Clerk clerk;

    public Consumer(Clerk clerk) {
        this.clerk = clerk;
    }

    @Override
    public void run() {
        for (int i = 0; i < 20; i++) {
            clerk.sell();
        }

    }
}